Underdeck tunnel for tankers



Dec. 10, 1963 J. v. c. MALCOLMSON ETAL 3,113,544v

UNDERDECK TUNNEL F OR TANKERS Filed July 12, 1962 2 Sheets-Sheet l QM mm 3 "W P A I. m FLU, A

Dec. 10, 1963 2 SheetsSheet 2 Filed July 12, 1962 United States Patent 3,113,544 UNDERDECK TUNNEL FGR TANKERS James V. C. Malcolmson, New York, N.Y., and David L. Butts, Chatham, Ni, assignors to Texaco inc, New York, N.Y., a corporation of Delaware Filed July 12, 1962, Ser- No. 209,359 2 Claims. (Cl. 11474) This invention relates to ship construction, and more particularly to the construction of ocean-going tankers. In its more specific aspect, this invention relates to an underdeck tunnel for ocean-going tankers.

In the construction of the hull of a tanker, there is provided on the center longitudinal line of the ship a foreand-aft girder attached to the main deck. This girder, usually referred to as the center longitudinal deck girder,

serves as a longitudinal strength member. On the main deck of the tanker there is provided an elevated runway,

commonly referred to as a catwalk or crews gangway, which usually extends along the deck from poop house to midship house and/or from midship house to forecastle deck. The catwalk affords relatively safe passageway for crew members when the deck is awash in stormy weather.

In addition, tanker construction involves a considerable network of piping, conduits, cables, etc. necessary for the operation of the ship, and include, for example, steam and water supply lines, sanitary lines, compressed air lines, electric cables and the like. However, this network of lines must be accessible for repairs or replacement, and for this reason substantial number of lines are run on deck, and often below the catwalk. As a consequence, access to the lines may be exceedingly difficult, or impossible, in stormy weather. In addition, the exposed position of these lines causes damage and corrosion with resulting high maintenance costs.

This invention has therefore as its main object to provide in a tanker construction an underdeck tunnel which does not require modification or alteration in hull construction of the center longitudinal deck girder, and utilizes the girder for support. As another object, the underdeck tunnel provides protective passageway for personnel, a protective housing for piping, conduits, cables, etc., which are ordinarily run on deck, and elimination of the conventional catwalk from the main deck thereby resulting in a relatively unobstructed deck. These together with other objects and advantages will best be understood by referring to the detailed description of the invention, and the accompanying drawings in which:

FIGURE 1 is a plan view in miniature lengthwise and partially fragmentary through a ship embodying the features of this invention;

FIGURE 2 is a transverse view in cross section taken of the ship shown in FIGURE 1; and

FIGURE 3 is an enlarged cross sectional view of the underdeck tunnel.

In general, the invention includes in a tanker structure a ma n deck or upper deck running from the bow to the stern of the vessel. A center longitudinal deck girder extends downwardly from the main deck, and a longitudinal tunnel extends below the deck and runs adjacent the girder. The tunnel is surrounded on the sides and bottom by a colierdam, and the girder forms a side outer-wall of the coiferdam. In addition, a duct adjacent the underside of the deck extends laterally through the tunnel and cofferdam and opens to the cargo tank of the tanker.

Referring to the drawings wherein like numerals designate similar parts throughout, there is shown an ocean going tanker designated generally by the numeral 16 In the hull structure of the tanker, there is a steel shell 12, and shell longitudinals 14 in spaced relationship along the bottom and sides of the shell. Also, a keel 1d extends longitudinally on the bottom of the ship. Deck longitudinals 18 are suitably spaced across the top and are covered with deck plating 29 to form the main deck for the tanker. In addition, the hull structure is provided with suitable transverse shell frames and transverse deck girders (not shown). The shell longitudinals, deck longitudinals, keel and transverse frames provide longitudinal and transverse strength and unite the structure as a whole.

The hull of the tanker is divided by two longitudinal bulkheads 22 which extend between the main deck and the bottom of the ship. The shell and bulkheads define the cargo tank 24, including Wings 24a and 24b which may have incorporated therein wing tanks (not shown).

Center longitudinal deck girder 26 extends substantially throughout the full length of the ship on the center line of the ship. The girder extends downwardly from the main deck, and serves as a longitudinal strength member attached to the deck.

A cofferdam bulkhead, indicated generally by the numeral 28, extends downwardly from the main deck into tank 24 of the tanker and runs fore-and-aft of the vessel. It will be observed that in this embodiment the cofferdam is located to the starboard side of the center line of the tanker thereby utilizing center deck girder 26 as a side outer-wall of the cofferdam as well as a strengthening member for supporting the coiferdam. In the construc tion of the cofiferdam a plurality of substantially U-shaped frames 39 are extended transversely from the starboard side of the center girder and downwardly from the main deck. The frames, which preferably are of a height less than the transverse depth of the center girder, are spaced apart at suitable intervals and are substantially parallel with each other. Steel plating is laid transverse to the frames 39 along the sides and bottoms thereby forming in conjunction with the center deck girder a pair of spaced parallel walls a, b and c, at extending downwardly from the main deck and joined along the bottom by spaced parallel walls e, f. (See FIGURE 3.) The spaced walls thus form a fluid-tight compartment or cofferdam 31 (FIGURE 1) extending longitudinally of the tanker. Thus, the center longitudinal girder serves as a side outer-wall of the cofferdam. It will be observed that by reason of this feature, the cofierdarn may be located to the port side of the center line of the tanker as well as to the starboard side.

The inside dimension of U-shaped frames St? is suflicient such that the inner walls or" the cofferdam define a passageway or tunnel 32 adequate to accommodate personnel as well as piping, conduits, cables and the like (indicated generally at 33). It thus will be observed that the cofferdam surrounds tunnel 32 on the sides and bottom. The tunnel extends longitudinally for a substantial length of the ship, the desirable length depending largely upon the construction and requirements for the tanker. As illustrated in the drawings, the tunnel extends from the amidship house or bridge house 3 5 to the after house 36, but where desired the tunnel may extend also from the amidship house to the forecastle indicated at 37. The

tunnel may be provided with transverse frames 38 (see FIGURE 3) for transverse support. In the event the colferdam is constructed on the port side of the center longitudinal girder, the tunnel extends longitudinally on the port side.

Referring to FIGURE 3, one or more manholes it), having a protective cover (not shown) which is desirably nearly flush with the top surface of the deck to eliminate protuberances, are located along the surface of the deck and over the colferdam to provide access into the cofferdam. In the event repairs are ever required of the cofferdam or of those parts of the tanker accessible from the cofierdam, a man may enter the cofferdam through the manhole. In addition, the coiferdam is equipped with a gas detection device (not shown) which is connected to a suitable system to warn of any leakage of cargo into the cofferdam.

Tunnel 3?; is provided with a longitudinal hand rail 42 which may be supported by the wall of the tunnel by conventional bracket means. The tunnel is further equipped with suitable light fixtures and also suitable exhaust means to provide adequate ventilation (not shown). In addition, the door of the tunnel is provided with one or more drain pots 44 which extend downwardly into the coiierdarn for a depth less than depth of the cofferdam as defined by the spaced walls 2, j". The drain pot is covered with a perforated plate which desirably is substantially flush with the floor of the tunnel to eliminate protuberances. Pipe 46 extending from the drain pot opens to a suction line 48 passing through the tunnel. In the event liquids accumulate in the tunnel, the liquid collects in the drain pot and is pumped therefrom by means of the pipe and suction line.

An equalizer duct 50 runs adjacent the underside of the deck and extends laterally through the tunnel 32 and coiferdam 3i and opens at each end to the cargo tank 24- of the tanker. As shown in the drawings, the duct abuts the under side of the deck and may be secured to the deck by any suitable means such as welding, or the like. The equalizer duct is particularly important in loading. The cargo hatches 52 on the main deck having vent system 53 for venting the cargo tank 24 are located on the port side of the ship. When the cargo, for example crude oil, furnace oil, refined products, etc., rises in the cargo tank to the level of the cofierdam, air or vapor can be trapped in the upper part of the cargo space on the starboard side of the cofferdam if no means of escape is provided. Entrapment of the vapor prevents complete filling of the hold. However, the equalizer duct vents the air or vapor to the other side of the tunnel and cofierdam, which then escape readily from the cargo tank through the cargo hatch and vent system. As a consequence, the hold may be filled to capacity.

It will be observed that the tunnel provides a protected passageway for personnel throughout a substantial length of the ship which is particularly important during heavy or stormy weather. Equally important, numerous piping, conduits, cables, etc. which in conventional construction are run on deck below the catwalk are contained within the underdeck tunnel. This is particularly important in that the tunel affords complete protection for these various lines and further pro vides ready and easy access for purposes of repairs or replacements. Because of this two-fold function of the tunnel, which is substantially surrounded on the sides and bottom by the tank cargo space, the tunnel is protected by a col'rerdam. For example, no cargo loaded in the tank cargo space can lcak intosthe tunnel unless there is rupture first in the outer wall'of the coftcrdam. If this should occur, the rupture may be detected upon inspection or by suitable detection means, and therefore repaired before any hazardous condition is created in the tunnel.

As a still further advantage of our invention, the catwalk and considerable piping are eliminated from the main deck thereby providing a relatively unobstructed deck. Equally important, our underdeck tunnel construction is integrated with the center longitudinal girder and utilizes the strength of the girder for support without alteration or modification of the construction. By reason of this feature, there is no necessity for deepening excessively the center girder which would require substantial alteration of the hull of the tanker.

Having described our invention and certain embodiments thereof, we claim:

1. In a tanker having a deck and a center longitudinal deck girder extending downwardly therefrom. a longitudinally extending coilerdam structure projecting into the car o space below said deck and comprising spaced parallel walls on both sides and bottom thereof, said deck girder forming a side outer-wall of said cofierdam structure, and a plurality of U-shaped frames in spaced relationship to each other between said parallel walls extending laterally from said girder and downwardly from said deck thereby supporting said parallel walls, the inner walls of said cofferdam structure defining an underdeck tunnel.

2. In a tanker as defined in claim 1, said cofferdam structure including means defining an open end duct extending along the underside of said deck and laterally through said cotierdam structure thereby providing communication between opposite sides thereof.

References Cited in the tile of this patent UNITED STATES PATENTS 126,353 Warden Oct. 24, 1871 2,560,269 Berner July 10, 1951 2,600,015 Mcaaughlin June 10, 1952 2,979,009 Sorrnan Apr. 11, 1961 3,633,150 Pickcrell May 8, 1962 OTHER REFERENCES 21,445 reat Britain of 1911 209,166 Great Britain Jan. 3, 1924 824,096 Great Britain Nov. 25, 1959 825,717 Great Britain Dec. 23, 1959 832,880 Great Britain Apr. 13, 1960 

1. IN A TANKER HAVING A DECK AND A CENTER LONGITUDINAL DECK GIRDER EXTENDING DOWNWARDLY THEREFROM, A LONGITUDINALLY EXTENDING COFFERDAM STRUCTURE PROJECTING INTO THE CARGO SPACE BELOW SAID DECK AND COMPRISING SPACED PARALLEL WALLS ON BOTH SIDES AND BOTTOM THEREOF, SAID DECK GIRDER FORMING A SIDE OUTER-WALL OF SAID COFFERDAM STRUC TURE, AND A PLURALITY OF U-SHAPED FRAMES IN SPACED RELATIONSHIP TO EACH OTHER BETWEEN SAID PARALLEL WALLS EXTENDING LATERALLY FROM SAID GIRDER AND DOWNWARDLY FROM SAID DECK THEREBY SUPPORTING SAID PARALLEL WALLS, THE INNER WALLS OF SAID COFFERDAM STRUCTURE DEFINING AN UNDERDECK TUNNEL. 